BASIRI BRISTONE, NORHAFIZAH MD ZAIN*, SHAMSUL MUHAMAD, CHNG HUCK YWIH AND LAILA NAHER*
Faculty of Agro-Based Industry, University Malaysia Kelantan, Jeli Campus, 17600 Jeli, Kelantan, Malaysia
*(e-mail : norhafizah.mz@umk.edu.my; Contact : 609-9477459)
(Received : February 24, 2022; Accepted : March 14, 2022)
ABSTRACT
Ethyl acetate extract of Parthenium hysterophorus leaves was fractionated through vacuum liquid
chromatography resulting in nine main fractions which were tested against germination, plumule, and
radicle lengths of Echinochloa colona and Hedyotis verticillata. Fractions 5 and 6 completely inhibited the
germination of the bioassay weeds. The presence of five major bioactive compounds [stigmasterol (ST),
ursodeoxycholic acid (UDCA), naphthalene (NAP), bis (2-ethylhexyl) adipate (DEHA) and bis (2-ethylhexyl)
phthalate (DEHP)] was confirmed through GC-MS in these fractions. Dose-response studies were carried
out at 0.5, 1.0, 1.5 and 2.0 mg/ml and 0.5, 1.0, 1.5 and 2.0 kg a.i./ha in the laboratory and greenhouse,
respectively. In the laboratory experiments, DEHA and DEHP exhibited potent inhibition on germination
(P<0.05) of E. colona and H. verticillata by 82-86 and 83-91%, respectively, at the highest concentration of
2.0 mg/ml. All the five compounds inhibited seed germination ranging from 61-73% for E. colona and 35-
40% for H. verticillata under greenhouse. Plumule length of H. verticillata was strongly suppressed at 2.0
mg/ml of UDCA with 80% inhibition under laboratory, while 57% inhibition was obtained under greenhouse
at 2.0 kg a.i./ha. Similarly, radicle length was suppressed with >90% on both the species under laboratory
by UDCA. However, in the greenhouse UDCA was more phytotoxic to E. colona with a 72% reduction in
radicle length as compared to H. verticillata with 42% radicle retardation. The present study revealed
that DEHP, DEHA and UDCA could be potential sources of natural herbicide.
Key words : Bioactive compounds, bioassay species, germination inhibition, herbicidal activity, plumule, radicle length, P. hysterophorus